This invention relates to a safety device in the form of an excess pressure relieving valve for use with fluid pressure reducing apparatus. For example, the excess pressure means of this invention are useful in connection with fluid pressure reducing apparatus such as that illustrated in U.S. Letters Pat. No. 3,712,333. The patent illustrates a regulator designed primarily for controlling the flow of carbon dioxide gas and oxygen and maintaining a desired outlet pressure regardless of a drop in the inlet pressure. It is important to relieve excess pressures, for the safety of personnel and equipment, as may occur as a result of a fractured seal or other valve component. Excess pressures may occur for any of a number of reasons including leakage or opening of the valve over outlet setting.
The valve of the patent illustrates the use of an exhaust port for relieving minor excesses in pressure. However, when such valves fail so as to permit substantial surges of fluid under high pressure, the restricted passageway contemplated in the patent, especially when used with carbon dioxide which often freezes blocking such restricted passages is inadequate. Accordingly, it is an important object of this invention to provide a safety device in the form of pressure relieving valve means for use in pressure reducing apparatus which is positive in action and which responds quickly to vent fluid under excess pressure from the reduced pressure chamber of such valves. Pressure relieving devices heretofore on the market are generally spring loaded in line devices which lag or are slow to operate because of the relatively strong spring necessitated in such apparatus.
Another important object of the invention is to provide a versatile safety device which may be used with a variety of fluid pressure reducing valves which lends itself to miniaturization and relatively inexpensive construction.
Another object of the invention is to provide a self-adjusting safety valve operable at a predetermined overpressure to operate with a variety of output pressure settings.